Digital microfluidic delivery device

Abstract

An active molecule delivery system whereby active molecules can be released on demand and/or a variety of different active molecules can be delivered from the same system and/or different concentrations of active molecules can be delivered from the same system. The invention is well-suited for delivering pharmaceuticals to patients transdermally. In some embodiments, the system includes two separate reservoirs and a mixing area thereby allowing precursors to be mixed immediately before transdermal delivery.

The invention claimed is: 
     
       1. An active molecule delivery system comprising:
 a first substrate comprising:
 a plurality of driving electrodes, 
 a dielectric layer covering the plurality of electrodes, and 
 a first hydrophobic layer covering the dielectric layer; 
 
 a second substrate comprising:
 a common electrode, 
 a second hydrophobic layer covering the common electrode; 
 
 a spacer separating the first and second substrates and creating a microfluidic region between the first and second substrates; 
 a plurality of reservoirs in fluidic communication with the plurality of driving electrodes; 
 a porous diffusion layer coupled to the first substrate on a side of the substrate opposed to the first hydrophobic layer, wherein the first substrate comprises a passage providing fluidic communication between the hydrophobic layer and the porous diffusion layer; 
 a mixing region in fluidic communication with each of the plurality of reservoirs and the passage; 
 and 
 a controller operatively coupled to the driving electrodes and configured to provide a voltage gradient between at least two driving electrodes. 
 
     
     
       2. The active molecule delivery system of  claim 1 , wherein each driving electrode is coupled to a thin-film-transistor. 
     
     
       3. The active molecule delivery system of  claim 1 , further comprising a plurality of passages providing fluidic communication between the hydrophobic layer and the porous diffusion layer. 
     
     
       4. The active molecule delivery system of  claim 1 , wherein the driving electrodes are flexible. 
     
     
       5. The active molecule delivery system of  claim 1 , wherein the passage includes capillary tubes or wicking fibers. 
     
     
       6. The active molecule delivery system of  claim 5 , wherein the capillary tubes or wicking fibers are coated with a hydrophobic coating. 
     
     
       7. The active molecule delivery system of  claim 1 , further comprising a plurality of passages providing fluidic communication between the hydrophobic layer and the porous diffusion layer, wherein each reservoir is in fluidic communication with only one passage. 
     
     
       8. The active molecule delivery system of  claim 1 , wherein the porous diffusion layer comprises acrylate, methacrylate, polycarbonate, polyvinyl alcohol, cellulose, poly(N-isopropylacrylamide) (PNIPAAm), poly(lactic-co-glycolic acid) (PLGA), polyvinylidene chloride, acrylonitrile, amorphous nylon, oriented polyester, terephthalate, polyvinyl chloride, polyethylene, polybutylene, polypropylene, polyisobutylene, or polystyrene. 
     
     
       9. The active molecule delivery system of  claim 1 , further comprising a biocompatible adhesive in contact with the porous diffusion layer. 
     
     
       10. A method for delivering an active molecule to the skin of a subject, comprising:
 providing an active molecule delivery system including:
 a first substrate comprising a plurality of driving electrodes, a dielectric layer covering the plurality of electrodes, and a first hydrophobic layer covering the dielectric layer, 
 a second substrate comprising a common electrode and a second hydrophobic layer covering the common electrode, 
 a spacer separating the first and second substrates and creating a microfluidic region between the first and second substrates, 
 first and second reservoirs in fluidic communication with the plurality of driving electrodes, 
 a mixing area in fluidic communication with both the first and second reservoirs, 
 a porous diffusion layer coupled to the first substrate on a side of the substrate opposed to the first hydrophobic layer, wherein the first substrate comprises a first passage providing fluidic communication between the hydrophobic layer and the porous diffusion layer, and 
 a controller operatively coupled to the driving electrodes and configured to provide a voltage gradient between at least two driving electrodes; 
 
 coupling the porous diffusion layer to skin of a subject; 
 moving a solution comprising an active molecule from a driving electrode to the first passage providing fluidic communication between the hydrophobic layer and the porous diffusion layer, wherein the solution comprising an active molecule is held in the first reservoir until the solution comprising an active molecule is required for delivery; and 
 allowing the active molecule to pass from the porous diffusion layer to the skin of the subject. 
 
     
     
       11. The method of  claim 10 , wherein the first reservoir contains a first solution comprising the active molecule at a first concentration and the second reservoir contains a second solution comprising the active molecule at a second concentration. 
     
     
       12. A method for delivering an active molecule to the skin of a subject, comprising:
 providing an active molecule delivery system including:
 a first substrate comprising a plurality of driving electrodes, a dielectric layer covering the plurality of electrodes, and a first hydrophobic layer covering the dielectric layer, 
 a second substrate comprising a common electrode and a second hydrophobic layer covering the common electrode, 
 a spacer separating the first and second substrates and creating a microfluidic region between the first and second substrates, 
 first and second reservoirs in fluidic communication with the plurality of driving electrodes, 
 a mixing area in fluidic communication with both the first and second reservoirs, 
 a porous diffusion layer coupled to the first substrate on a side of the substrate opposed to the first hydrophobic layer, wherein the first substrate comprises a first passage providing fluidic communication between the hydrophobic layer and the porous diffusion layer, and 
 a controller operatively coupled to the driving electrodes and configured to provide a voltage gradient between at least two driving electrodes; 
 
 coupling the porous diffusion layer to skin of a subject; 
 moving a solution comprising an active molecule from a driving electrode to the first passage providing fluidic communication between the hydrophobic layer and the porous diffusion layer, 
 wherein the first reservoir contains a first solution comprising a first precursor molecule and the second reservoir contains a second solution comprising a second precursor molecule, and wherein delivering an active molecule to the skin of a subject further comprises: 
 mixing the first precursor molecule with the second precursor molecule to create a mixture; and 
 moving the mixture to the first passage providing fluidic communication between the hydrophobic layer and the porous diffusion layer; and 
 allowing the active molecule to pass from the porous diffusion layer to the skin of the subject. 
 
     
     
       13. The method of  claim 12 , wherein the first precursor molecule is an antibody. 
     
     
       14. The method of  claim 12 , wherein the first precursor is an oligonucleotide. 
     
     
       15. The method of  claim 12 , wherein the mixture comprises an opioid.